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Biomedical subjects

H Graf

Publications and source records attributed to H Graf.

At least 91 records · Page 5Linked to original sources
PubMed1991

[The colloid osmotic pressure of blood. Physiology, measuring technique and pre-analytic factors of influence].

Since the fundamental work of Starling the central of colloid osmotic pressure for maintaining volume homoeostasis and for transcapillary fluid exchange has been well known. To treat an intravasal volume deficit colloidal plasma substitution solutions are able to secure a sufficient colloid osmotic pressure. The last one can be measured by oncometry. Therefore an individual therapy is possible. This review describes the physiologic function, measurement techniques and important influencing parameters and disturbing factors which may be taken into consideration when colloid osmotic pressure is determined.

Blood Proteins↗
PubMed1991

[Effect of electrically powered dental devices on cardiac parameter function in humans].

Electrically powered devices represent a hazard for patients with cardiac pacemakers. The aim of the present investigation was an in vivo evaluation of possible interactions between electrically powered dental instruments and the function of artificial pacemakers in humans. In 26 patients with artificial pacemakers, different dental instruments were applied, including air scaler, ultrasonic curets, electric pulp tester and electrotome. These devices were applied at highest intensity. Immediately prior to, during, and immediately after applications of these instruments, the pulse rate and the electrocardiogram (EKG) were recorded. The EKG recordings were assessed for irregularities in the distances between the pacemaker peaks. The dental devices were assessed for magnetic fields or induction tension. The results showed that none of the dental devices caused an irregularity in the pacemaker function. The air scaler, Piezon ultrasonic curet and the electric pulp tester caused no measurable magnetic fields. The Sonus 2 ultrasonic curet and the electrotome magnetic fields were measured up to 60 and 50 cm, respectively. All dental devices caused induction tension. The highest value was produced by the electrotome. It seems that cardiac pacemaker function is not affected by electrically powered dental devices. However, there remains a risk in relation to older pacemakers or defective dental devices.

Adult↗
PubMed1991

[Episodic progression of periodontitis--histologic associations].

Periodontal lesions are primarily diagnosed using the periodontal probe. Using site-specific probing attachment level measurements in defined time intervals, dentists can identify patients and dentition segments that suffer temporarily from a high periodontitis progression rate. The present article describes whether sites where clinical measurements suggested a high progression rate had tissue characteristics different from nonprogressing sites. Ten patients with untreated advanced adult periodontitis were monitored for 10 months by measuring clinical parameters every 30 days. These parameters were gingival index, plaque index, bleeding index, bleeding on probing, probing depth and probing attachment levels. Every month pairs of contralateral sites were sought where one site had lost 2 mm (P-2) or more (P greater than 2) probing attachment (P-sites) and the other site had not (C-site). From these sites supracrestal soft tissue biopsies were taken. After histological processing, a first analysis determined the number of inflammatory cells in 9 standard areas in P- and C-biopsies. A second analysis evaluated cell populations at the apical end of the junctional epithelium. The results showed that bleeding on probing, probing depth and probing attachment loss were statistically significantly greater at P-sites. At C-sites there were only few inflammatory cells. At P-2-sites there were numerous inflammatory cells, and in P greater than 2-sites the number of these cells was statistically significantly greater than in corresponding control sites. The cell populations at the apical end of the junctional epithelium were different between P- and C-sites. At P-sites, the percentage of mast cells, monocytes/macrophages and plasma cells was statistically significantly greater than at C-sites. At C-sites, the percentage of fibroblasts was statistically significantly greater than at P-sites. These results demonstrate that clinical probing identifies episodes of periodontitis progression, which are associated with pronounced changes in tissue characteristics, namely greater numbers of inflammatory cells.

Dental Plaque Index↗
PubMed1991

Episodic probing attachment loss versus pocket depth: bacterial morphotype associations.

Marginal periodontitis in humans is characterized by phases of clinical disease progression, which are interspersed between periods of quiescence. The purpose of the present study was to compare subgingival bacterial populations from periodontal sites undergoing episodic probing attachment loss with bacterial populations from non-progressing lesions. Probing depth and attachment levels were measured in 10 adult patients at baseline, and every 30 days thereafter for 10 months. Pairs of corresponding contralateral sites were identified where one site had lost probing attachment within the previous month (P) and the other site had not (C). Subgingival bacterial samples were obtained from these sites and analyzed using darkfield microscopy. Motile forms, spirochetes, curved and straight rods, filaments, coccoid cells, fusiforms, and the total number of bacteria were assessed. The results showed that median pocket depth and attachment change were statistically significantly greater in P-sites as compared to C-sites. There was no significant difference in bacterial populations between P- and C-sites (p greater than 0.15). Motile forms, spirochetes, and total number of bacteria were positively correlated with pocket depth in P-sites, while in C-sites the same was true only for curved rods. These results suggest that darkfield microscopy of subgingival bacteria in humans represents primarily pocket depth.

Adult↗
PubMed1991

Digital vascular reactivity in patients on haemodialysis treated with human recombinant erythropoietin.

Digital vascular reactivity was determined in 12 normotensive patients on chronic hemodialysis without a history of Raynaud's phenomenon before and after partial correction of anaemia with human recombinant erythropoietin (rHuEPO): apparent finger systolic pressures and finger skin temperatures were recorded at rest, after local cooling, and following 5 minutes rewarming time. Finger systolic pressures remained constant during the whole test, pre and post rHuEPO therapy. The decrease in finger skin temperatures after cold provocation as well as the rewarming behaviour after cooling were normal in both examinations. The present data indicate that treatment with EPO does not interfere with digital arterial reactivity in normotensive patients on haemodialysis.

Adult↗
PubMed1990

[The significance of erythropoietin for nephrology].

The analysis of the structure of erythropoietin and the subsequent production of recombinant human erythropoietin opened a new era in the understanding of the pathogenesis and therapy of renal anaemia. From the diagnostic point of view sufficiently accurate radioimmunoassays are currently available to throw new light on the pathogenesis of renal anaemia, and enable pharmacokinetic studies of the recombinant hormone to be carried on. For the first time a causal therapy is available for renal anaemia. The following review summarizes the consequences of these innovations on the different aspects of nephrology.

Anemia↗
PubMed1990

[Sodium dichloroacetate--a substance with manifold therapeutic potential].

The therapeutic potential of sodium dichloroacetate (DCA) formerly called vitamin B 15, has already been under investigation for the past few years. The predominant property of DCA underlying its therapeutic action is activation of pyruvate dehydrogenase. The potential therapeutic use of DCA in the treatment of lactic acidosis and type II diabetes mellitus related directly to its stimulatory effect on this enzyme. Additional favourable effects of DCA on cardiac performance in states such as ischaemia, where glucose becomes a major energy-yielding substrate, have also been demonstrated. Treatment of lipid disorders might become further indications for the implementation of this substance. DCA inhibits hydroxy-methyl-glutaryl CoA reductase, thus lowering cholesterol and triglyceride levels. Earlier suggestions that DCA produced a major degree of acute toxicity were not confirmed in recent studies using DCA of established purity and homogeneity. These findings and recent evidence suggesting a potentially important role of DCA in the treatment of lactic acidosis are the reason and basis for a review of the established actions of this substance.

Acetates↗
PubMed1990

Comparison of serological and DNA probe analyses for detection of suspected periodontal pathogens in subgingival plaque samples.

Several methods are currently being used to identify specific bacteria in dental plaque, namely direct culture, serological techniques and DNA probes. Culture methods are labour-intensive, dependent on the viability of the cells, and require fastidious growth conditions. Serological and DNA probes allow rapid strain-specific identification of periodontal pathogens with limited effort. The purpose of the present study was to compare results from serological and DNA probes in assessing and quantitating the presence of three suspected periodontal pathogens in subgingival plaque: Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bact. intermedius. Subgingival bacterial samples were obtained from 4 periodontal sites of each of 13 patients with untreated moderate to advanced adult periodontitis. Samples were taken using 2 paper points that were simultaneously inserted for 10 s to the bottom of the periodontal pockets. The plaque from one paper point was analysed by immunofluorescence using monoclonal antibodies. The other sample was analysed by species-specific cloned DNA probes. The number of bacteria per millilitre was calculated for both methods, and used for comparisons of results obtained with the two techniques. Results from indirect immunofluorescence and DNA hybridization analyses were negative for A. actinomycetemcomitans across all samples. Fluorescence did not detect bacteria at levels lower than 10(4), while the DNA probes identified organisms at levels of 10(3). Similar numbers of samples positive for Bact. gingivalis were obtained with either method (p = 0.227), and the results were not independent. A significantly greater proportion of Bact. intermedius-positive samples was detected by immunofluorescence (p = 0.0039), and the results of immunofluorescence and DNA hybridization were independent.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus↗
PubMed1990

Decreased peripheral insulin sensitivity in acromegalic patients.

In 13 nondiabetic acromegalic patients glucose homeostasis was studied by use of the hyperglycaemic clamp technique and compared to a group of sex and age matched and a group of sex, age and weight matched controls. When compared to a control group of normal weight glucose stimulated insulin release (I) was significantly increased and tissue sensitivity to insulin (M/I) significantly decreased. However, no significant differences were observed when the parameters were compared with a weight matched group. Glucose stimulated insulin release correlated positively with growth hormone (GH) and somatomedin-C levels, whereas no such a correlation could be obtained for M/I. Thus, chronic growth hormone excess seems to induce hyperinsulinaemia which in turn leads to obesity and metabolic changes comparable to those of obesity.

Acromegaly↗
PubMed1990

Episodic probing attachment loss in humans: histologic associations.

Marginal periodontitis in humans is characterized by episodes of probing attachment loss followed by periods of quiescence. The purpose of the present study was to assess characteristics of the inflammatory infiltrate in periodontal lesions where episodic probing attachment loss had occurred within the previous month. In 10 systemically healthy adult human subjects with untreated advanced periodontitis, probing attachment levels were measured at baseline and every 30 days thereafter for 10 months. Measurements were made at six sites of every tooth using an acrylic onlay as a reference point and a pressure sensitive probe. Sites where double measurements confirmed that probing attachment loss of 2 mm or more had occurred within the previous month were identified (P-sites), as were corresponding contralateral non-progressing sites (C-sites). Biopsies of the supracrestal tissues were taken from these sites, processed, and cut in 1 mu sections for histologic evaluation. Counts of inflammatory cells in standard areas of the sections were compared between P and C sites. The results indicated that 5.04% of 1566 sites under investigation lost probing attachment during the 10-month observation period. Inflammatory cell counts were higher in P-sites as compared to C-sites. P-sites with more than 2 mm attachment loss (P greater than 2 sites) had significantly more inflammatory cells within standard areas at the apical end of the junctional epithelium than non-progressing C-sites (P less than 0.02). There was no significant difference in counts between P-sites progressing 2 mm (P-2 sites) and corresponding C-sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[The value of fructosamine in hemodialysis patients].

Fructosamine is thought to be an alternative diabetic long term parameter to HbAlc. A possible advantage of fructosamine is the shorter half life of this parameter. Therefore changes in the metabolic control of diabetes can be evaluated faster. However, daily variations of protein concentrations limit the clinical usefulness of fructosamine, especially in patients on hemodialysis, where we see variations in total protein- and albumin concentration during dialysis. Due to these limitations we studied the clinical usefulness of a new fructosamine assay in 38 patients with chronic renal failure. Fructosamine values, total protein, albumin, blood glucose and creatinine were measured before and after three hours hemodialysis treatment as well as glycosylated hemoglobin. Before dialysis HbA1c correlated with HbA1c after dialysis (r = 0.99), which documents the usefulness of glycosylated hemoglobin in patients on hemodialysis. Fructosamine before dialysis shows a correlation with fructosamine values after dialysis of r = 0.77. After correction with total protein the correlation was r = 0.95, also after correction with albumin. Fructosamine values before and after dialysis correlated excellently (r = 0.95). Fructosamine values before and after dialysis can only be compared after correction with total protein or with albumin.

Blood Glucose↗
PubMed1989

Bacterial contamination of dialysate in dialysis-associated endotoxaemia.

Bacteriological investigations and endotoxin (ET) determinations were performed during a routine haemodialysis session for six patients. The glucose free dialysate was prepared with untreated tap water. All patients were dialysed for 5 h. Pseudomonas aeruginosa was regularly isolated in numbers up to 10(7) cfu ml-1 from samples of the dialysate inflow, the dialysate site and the dialysate outflow. ET levels in the plasma of the patients increased continuously during haemodialysis and were always higher in the blood outflow line of the dialyzer than in the blood inflow. Despite the high bacterial counts in the dialysate and the increasing ET levels in the patients plasma neither bacteraemia nor fever was observed. The former is due to the impermeability of the dialyzer membrane for bacteria, the latter is explained by low pyrogenicity of P. aeruginosa endotoxin. Inspection of the dialyzer machines revealed that air-traps and heater-unit for the incoming (untreated) tap water before mixing with the dialysate concentrate were the only sites where high bacterial release was feasible, as this part of the machine escaped disinfection due to the construction of these devices. We recommend the regular disinfection of all parts of a dialyzer machine, including heating units, air traps and valves.

Dialysis Solutions↗
PubMed1989

Anaemia and reduced exercise capacity in patients on chronic haemodialysis.

1. In order to evaluate the influence of varying degrees of anaemia on exercise capacity and haemodynamic parameters, 13 patients on chronic intermittent haemodialysis with haemoglobin levels between 5.1 and 12.2 g/100 ml were subjected to an exhaustive exercise test. Measurements during bicycle ergometry consisted of O2 uptake at the anaerobic threshold and of maximum O2 uptake. Resting haemodynamic parameters such as cardiac index, heart rate, stroke volume index and blood pressure were assessed non-invasively in the 13 patients undergoing exercise and in an additional three patients. 2. O2 uptake at the anaerobic threshold as well as maximum peripheral O2 uptake were severely impaired and were positively correlated with haemoglobin concentration. The strongest correlation was found between the impairment of O2 uptake at maximum workload, as assessed by maximum O2 uptake/predicted maximum O2 uptake, and haemoglobin concentration. Haemodynamic alterations in the resting state consisted of a cardiac index in the upper normal range and did not correlate with the haemoglobin concentration. 3. We conclude from our study that exercise capacity in patients on chronic intermittent haemodialysis is severely impaired and that the impairment of aerobic and anaerobic capacity is significantly correlated with the severity of renal anaemia.

Adult↗
PubMed1989

[Aerobic and anaerobic capacity of chronic hemodialysis patients under continuous therapy with recombinant human erythropoietin].

In earlier studies we have shown that partial correction of anemia by recombinant human erythropoietin (r-HuEPO) already after 12 weeks results in a significant increase of exercise capacity in patients on chronic hemodialysis. As causative effect increased oxygen availability with improved oxygen delivery to the tissues was assumed. To elucidate the long-term effects of a partial correction of anemia with r-HuEPO on exercise capacity, oxygen uptake at maximum exercise and at the anaerobic threshold was measured by repetitive spiroergometry. Measurements were done before, 3 months and 6 months after initiation of r-HuEPO therapy. The results are summarized below: (table; see text) Our results show that a long-term improvement of peripheral oxygen availability leads to a further increase of anaerobic threshold in patients on chronic hemodialysis even without a further increase of hemoglobin levels and without exercise training. It appears that elimination of the chronic hypoxic condition results in a restoration of previously diminished mitochondrial enzymes in muscle, particularly for aerobic glycolysis. Besides acute improvement of aerobic and anaerobic exercise capacity, the long-term administration of r-HuEPO with its increased anaerobic threshold enhances the patients' everyday life working capacity.

Erythropoietin↗
PubMed1989

L-carnitine substitution in patients on chronic hemodialysis.

Patients on chronic hemodialysis with hyperlipidemia were found to respond either with decreased levels (responders) or with a further increase of the plasma triglyceride levels (nonresponders) to a carnitine substitution therapy. The aim of the present study was to find possible predictors to distinguish between responders and nonresponders prior to the initiation of therapy. Since it is suggested that erythrocytes are involved in carnitine transport to tissues, it was of interest to determine plasma and erythrocyte carnitine concentrations in the hemodialyzed patients before and during carnitine substitution therapy and to compare the results with those of healthy controls. Before therapy, comparatively lower plasma levels of both free and total carnitine, but higher portions of short-chain acylcarnitine on total carnitine were found in all patients. In erythrocytes, the nonresponders showed significantly higher total carnitine levels, compared to responders and controls. After the start of carnitine substitution, the increase of total plasma carnitine during the substitution period corresponded with the carnitine dose administered in responders, in nonresponders the highest carnitine values were found in the second week when the lower carnitine dose was administered. The changes of the plasma short-chain acylcarnitine levels with time were very similar to those of plasma triglycerides. All patients showed a time-delayed accumulation of carnitine in erythrocytes and, interestingly, markedly higher concentrations in the second week when the lower carnitine dose was administered. The results of the present study demonstrate that the erythrocyte carnitine content is a reliable predictor to distinguish between responders and nonresponders prior to the start of a carnitine substitution therapy.

Carnitine↗